Vehicular exhaust resonance suppression system and sensing means therefore

Abstract

A resonance detection device is provided for detecting resonance in an exhaust passage of an automotive vehicle. The detection device employs a temperature sensor in combination with an arrangement which enables the sensor to be exposed to a flow of exhaust gas the temperature of which is different from the temperature of the bulk of the flow, when resonance occurs. In given embodiments the arrangement takes the form different diameter conduits and/or vessels, while others it takes the form of a heat exchange device which either heats or cools the gases, and which is disposed proximate the temperature sensor. When no resonance occurs in the passage, the output of the temperature sensor remains stable. When resonance occurs the fluid flow characteristics in the passage change in a manner wherein the gas which has been either heated or cooled by the heat exchange device is induced to flow against the temperature sensor. The sensed temperature change can be used to control a valve via which the resonance characteristics of the passage are modified and via which resonance is attenuated.

What is claimed is: 
     
       1. A resonance suppression device for an internal combustion engine comprising: an exhaust system, said exhaust system including a passage coupled to an exhaust outlet of an internal combustion engine for directing a flow of exhaust gasses expelled by said internal combustion engine;   tuning means for selectively altering a frequency at which gas in said exhaust system resonates;   a resonance detecting means, said resonance detecting means including a resonating chamber which is connected by a connector passage to said passage at a portion whereat an anti-node of a sound wave of said resonant frequency occurs, and a temperature sensor, said temperature sensor being disposed in said connector passage; and   control means, said control means being responsive to a signal output of said resonance detecting means for switching said tuning means in a manner which alters a resonance frequency of said exhaust system upon the detection of resonance by said resonance detecting means.   
     
     
       2. A resonance detection device comprising: a passage for conducting a flow of gas;   temperature detecting means for detecting the temperature of said gas in said passage at a portion of said passage whereat the gas within said passage flows in both axial directions of said passage as a result of resonance occurring within said passage; and   heat exchange means disposed within said passage in the near vicinity of said temperature detecting means for altering the temperature of gas proximate said temperature sensing means in response to resonance occurring in said passage.   
     
     
       3. In a resonance suppression device for an exhaust system of an automotive vehicle; a chamber, said chamber being in fluid communication with a first exhaust pipe section which supplies exhaust gases thereinto, and a second exhaust pipe section which exhausts exhaust gases therefrom, said camber having a cross-sectional area different than a cross-sectional area of said exhaust pipe sections;   a variable flow restricting means disposed in the first exhaust pipe section for selectively restricting said flow of exhaust gases into the chamber; and   temperature sensing means, said temperature sensing means being disposed in the first exhaust pipe section in vicinity of said variable flow restricting means, said temperature sensing means producing an electric temperature indicative signal which is used to control the variable flow restricting means.   
     
     
       4. A resonance detecting device as set forth in claim 4 wherein said chamber is defined by a portion of an exhaust passage of an internal combustion engine. 
     
     
       5. An exhaust system for an internal combustion system comprising: an exhaust passage for conducting exhaust gases of said internal combustion engine; PG,37   exhaust passage tuning means, said exhaust passage tuning means being operable for altering the resonating frequency of said exhaust passage;   temperature sensing means, said temperature sensing means being disposed within said exhaust passage for detecting the temperature of gases within said exhaust passage at a point defined in the vicinity of a resonance node of a sound wave occurring in said passage and outputting an electric temperature signal indicative thereof; and   electronic control means, said electronic control means being responsive to fluctuations in said temperature indicative signal for deriving a control signal which is supplied to said exhaust passage tuning means.   
     
     
       6. A resonance detecting device comprising: a passage through which gases flow, said passage having a first portion having a first cross-sectional area, and a second portion having a second cross-sectional area which is larger than the first cross-sectional area, said first and second portions being directly connected to one another; and   temperature sensing means, said temperature sensing means being disposed in said first portion at a location which is proximate the second portion, wherein a heating means is disposed in said first portion in the vicinity of said temperature sensor.   
     
     
       7. A resonance detecting device comprising: a passage through which gases flow, said passage having a first portion having a first cross-sectional area, and a second portion having a second cross-sectional area which is larger than the first cross-sectional area, said first and second portions being directly connected with one another; and   temperature sensing means, said temperature sensing means being disposed in said first portion at a location which is proximate the second portion, wherein a cooling element is disposed in said first portion in the vicinity of said temperature sensor for inducing localized cooling of the gases.   
     
     
       8. A resonance detecting device comprising: a passage through which gases flow, said passage having a first portion having a first cross-sectional area, which opens into a second portion having a different cross-sectional area; and   temperature sensing means, said temperature sensing means being disposed in a location of said first portion which is proximate the second portion,   wherein a cooling means is disposed in said first portion in the vicinity of said temperature sensor, and   wherein said cooling means comprises a heat pipe.   
     
     
       9. A resonance detecting device comprising: a passage through which gases flow, said passage having a first portion having a first cross-sectional area, and a second portion having a second cross-sectional area which is larger that the first cross-sectional area, said first portion being connected directly to said second portion at a location of said second portion whereat a pressure wave anti-node tends to occur, said first portion forming the only inlet for the second portion, and said second portion defining means which cools a flow of heated gas which flows thereinto from said first portion; and   temperature sensing means, said temperature sensing means being disposed in said first portion at a location which is proximate the second portion wherein a heating element is disposed within said first portion in the vicinity of said temperature sensing means.   
     
     
       10. A resonance detecting device comprising: a passage, said passage having an opening; and   temperature sensing means, said temperature sensing means being disposed within said passage in the vicinity of said opening for detecting the temperature of a fluid in said passage,   wherein said temperature sensing means is operatively coupled to a processing means, said processing means processing a signal output of said temperature sensor for producing a differential value representative of fluctuations in said temperature signal, and   wherein said processing means is operably connected to an actuator for a tuning means, said tuning means being operable for altering a resonance frequency of a passage.   
     
     
       11. A resonance detecting device as set forth in claim 10 wherein said tuning means is defined by a variable flow restricting arrangement, said variable flow restricting arrangement being operable for selectively restricting a flow of gasses within said passage. 
     
     
       12. A resonance detecting device comprising: a passage through which heated gases flow;   a temperature sensor; and   means which defines part of said passage for exposing said temperature sensor to a flow of gas the temperature of which is different from the bulk of the gas which flows through said passage, when resonance occurs in said passage.   
     
     
       13. A resonance detecting device comprising: a passage through which gases flow;   a conduit having an upstream end and a downstream end, said conduit being disposed with said passage so that both the upstream end and the downstream end open into said passage;   temperature sensing means, said temperature sensing means being disposed in said conduit and arranged to producing a signal indicative of the sensed temperature; and   a heat exchange element which is arranged to project into said conduit adjacent said temperature sensing means and which is arranged to remove heat from the gases flowing in said conduit.   
     
     
       14. A resonance detecting device comprising: a plurality of temperature sensors arranged at spaced intervals along a passage through which gases flow, said plurality of temperature sensors being disposed at a location where resonance tends to induce the gases in said passage to flow back and forth; and   heat transfer means disposed in the passage at a location proximate said plurality of temperature sensors for inducing a change in the temperature of the gases which tend to be carried back and forth over said plurality of sensors when resonance occurs.